1. Field of the Invention
The present invention relates to a driving device that drives a driven member and an optical apparatus including the driving device.
2. Description of the Related Art
A driving device has been known which includes actuators, each having a piezoelectric element that is expanded or contracted in response to a driving signal, and outputs the driving signal to each of the actuators to move a driven member (for example, see JP-A-11-155292). The driving device disclosed in JP-A-11-155292 stores the waveforms of the driving signals, changes the waveforms of the driving signals on the basis of a driving direction and a driving speed, and supplies the changed driving signals to the piezoelectric elements, thereby controlling the actuators.
The driving device disclosed in JP-A-11-155292 adopts a control method of repeatedly changing the operational state of each actuator between a driving state and a stop state in order to precisely move the driven member. In addition, when only one driving state and only one stop state are arranged between movement amount check times, there is a large difference between an expected value and an actual movement amount. Therefore, the following control method (decimation driving) is considered: a plurality of pulse signals continuously input to an actuator are decimated at a predetermined timing to set a plurality of stop states, and a driving state and a stop state are repeated between movement amount check times to reduce the difference between an expected value and an actual movement amount.
However, when the above-mentioned decimation driving method is applied to the driving device disclosed in JP-A-11-155292 to control a plurality of actuators at the same time, in the stop state, no current is consumed by the driving device. However, in the driving state, a current is supplied to all the actuators at the same time, and the instantaneous current consumed by the entire driving device is increased. As a result, the current consumption of a power supply becomes unstable, and the operation of the actuator becomes unstable.